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A system, device, and method for managing colors of a color printer by
printing color patches on a test sheet of paper associated with a paper
type, determining spectral data of the color patches using an inline full
width array spectrophotometer of the color printer, determining
measurements based on the spectral data, determining that a measurement
is equal to or within a range of a measurement associated with an
existing paper profile; and printing subsequent sheets of paper
associated with the paper type using parameters associated with the
existing paper profile.

Inventors:

OCHS; Matthew J.; (Webster, NY)

Applicant:

Name

City

State

Country

Type

XEROX CORPORATION

Norwalk

CT

US

Family ID:

1000002138329

Appl. No.:

15/048898

Filed:

February 19, 2016

Current U.S. Class:

1/1

Current CPC Class:

B41J 29/393 20130101; B41J 2/2132 20130101

International Class:

B41J 2/21 20060101 B41J002/21; B41J 29/393 20060101 B41J029/393

Claims

1. A method comprising: printing one or more color patches on a test
sheet of paper associated with a paper type; determining spectral data of
the one or more color patches using a full width array spectrophotometer;
determining measurements based on the spectral data; determining that at
least one of the measurements is equal to or within a range of a
measurement associated with an existing paper profile; printing
subsequent sheets of paper associated with the paper type using
parameters associated with the existing paper profile; printing one or
more color patches on a second test sheet of paper associated with a
second paper type; determining second spectral data of the one or more
color patches of the second test sheet using the full width array
spectrophotometer; and adjusting parameters of a printer based on
determining that one or more measurements based on the second spectral
data are not equal to or within a range of measurements associated with
existing paper profiles.

2. The method of claim 1, further comprising receiving instructions to
profile the test sheet of paper.

4. The method of claim 3, wherein the inkjet printer is an aqueous inkjet
printer.

5. The method of claim 3, wherein the full width array spectrophotometer
is an inline spectrophotometer of the inkjet printer.

6. The method of claim 1, wherein the spectral data further comprise
spectral data corresponding to the whiteness of the test sheet of paper.

7. The method of claim 1, wherein the full width array spectrophotometer
scans both sides of the test sheet of paper.

8. The method of claim 1, wherein the measurements comprise one or more
of color brightness, color gamut volumes, color contrast, ink
showthrough, or paper whiteness.

9. (canceled)

10. The method of claim 1, wherein the parameters comprise one or more of
total area coverage, ink limits, gray component replacement, or color
contrast.

11. The method of claim 1, further comprising performing a second method
until one or more new measurements associated with a new test sheet of
paper are equal to or within a range of target measurements, the second
method comprising: adjusting parameters of the printer based on one or
more measurements associated with a previous test sheet of paper;
printing one or more color patches on a new test sheet of paper
associated with the second paper type based on the adjusted parameters of
the printer; determining new spectral data of the one or more color
patches of the new test sheet of paper using the full width array
spectrophotometer; and determining new measurements based on the new
spectral data; and generating a new paper profile based on the adjusted
parameters that resulted in the one or more new measurements within the
range of target measurements.

12. The method of claim 11, wherein the parameters are iteratively
adjusted.

13. A system comprising: a printer; a processing system comprising one or
more processors capable of transmitting data to the printer; and a memory
system comprising one or more computer-readable media, wherein the one or
more computer-readable media contain instructions that, when executed by
the processing system, cause the processing system to perform operations
comprising: printing one or more color patches on a test sheet of paper
associated with a paper type; determining spectral data of the one or
more color patches using a full width array spectrophotometer;
determining measurements based on the spectral data; determining that at
least one of the measurements is equal to or within a range of a
measurement associated with an existing paper profile; printing
subsequent sheets of paper associated with the paper type using
parameters associated with the existing paper profile; printing one or
more color patches on a second test sheet of paper associated with a
second paper type; determining spectral data of the one or more color
patches of the second test sheet using the full width array
spectrophotometer; and adjusting parameters of a printer based on
determining that one or more measurements based on the second spectral
data are not equal to or within a range of measurements associated with
existing paper profiles.

14. The system of claim 13, wherein the printer is an aqueous inkjet
printer.

15. The system of claim 14, wherein the full width array
spectrophotometer is an inline spectrophotometer of the aqueous inkjet
printer.

16. The system of claim 13, wherein the full width array
spectrophotometer scans both sides of the test sheet of paper.

17. The system of claim 13, wherein the measurements comprise one or more
of color brightness, color gamut volumes, color contrast, ink
showthrough, or paper whiteness.

18. (canceled)

19. The system of claim 13, wherein the parameters comprise one or more
of total area coverage, ink limits, gray component replacement, or color
contrast.

20. The system of claim 13, the operations further comprising performing
a second method until one or more new measurements associated with a new
test sheet of paper are equal to or within a range of target
measurements, the second method comprising: adjusting parameters of the
printer based on one or more measurements associated with a previous test
sheet of paper; printing one or more color patches on a new test sheet of
paper associated with the second paper type based on the adjusted
parameters of the printer; determining new spectral data of the one or
more color patches of the new test sheet of paper using the full width
array spectrophotometer; and determining new measurements based on the
new spectral data; and generating a new paper profile based on the
adjusted parameters that resulted in the one or more new measurements
within the range of target measurements.

Description

BACKGROUND

[0001] There are numerous different types of printer paper available for
printing documents. Additionally, the type of paper can have a large
effect on the resulting documents. For example, particularly when using
water-based inkjet printers, certain paper types can cause colors to be
brighter, can increase or decrease the color gamut volumes (subset of
colors available), and/or can affect the contrast between colors and/or
between the colors and the paper (e.g., the contrast between black text
and the whiteness of the paper).

[0002] Accordingly, parameters of an inkjet printer that result in
suitable printed color documents with one type of printer paper may not
be suitable for other types of printer paper.

[0003] Therefore, inkjet printer technology can be improved by methods,
systems, and devices for efficiently managing parameters, such as color
management controls, of an inkjet printer.

SUMMARY

[0004] The present disclosure relates to systems, devices, and methods for
managing colors of a color printer by printing color patches on a test
sheet of paper associated with a paper type, determining spectral data of
the color patches using a full width array spectrophotometer, determining
measurements based on the spectral data, determining that a measurement
is equal to or within a range of a measurement associated with an
existing paper profile; and printing subsequent sheets of paper
associated with the paper type using parameters associated with the
existing paper profile.

[0005] In some embodiments, printing the color patches can be based on
receiving an instruction to profile the test sheet of paper.

[0006] In further embodiments, the color printer can be an inkjet printer,
such as an aqueous inkjet printer.

[0007] In some embodiments, the full width array spectrophotometer can be
an inline spectrophotometer of an inkjet printer.

[0008] In other embodiments, the full width array spectrophotometer can
scan both sides of the test sheet of paper.

[0009] In various embodiments, the spectral data can include spectral data
corresponding to the whiteness of the test sheet of paper.

[0011] In some implementations, the color printer can print color patches
on a second test sheet of paper associated with a second paper type,
determine spectral data of the color patches of the second test sheet
using the full width array spectrophotometer, and adjust parameters of
the color printer based on determining that a measurement is not equal to
or within a range of measurements associated with existing paper
profiles.

[0012] In further implementations, the adjusted parameters can include,
for example, total area coverage, ink limits, gray component replacement,
or color contrast.

[0013] In some embodiments, the color printer can repeatedly perform a
second method until new measurements associated with a new test sheet of
paper are equal to or within a range of target measurements, the second
method can include: adjusting parameters of the color printer based on
measurements associated with a previous test sheet of paper; printing
color patches on a new test sheet of paper associated with the second
paper type based on the adjusted parameters of the color printer;
determining new spectral data of the color patches of the new test sheet
of paper using the full width array spectrophotometer; and determining
new measurements based on the new spectral data. Based on adjusted
parameters that resulted in the new measurements within the target range,
a new paper profile can be generated.

[0014] In further embodiments, the parameters can be iteratively adjusted.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute
a part of this specification, illustrate various embodiments of the
present disclosure and together, with the description, serve to explain
the principles of the present disclosure. In the drawings:

[0017] FIG. 2 is a diagram depicting a schematic side view of one example
of an FWA spectrophotometer shown scanning a printed sheet in the output
path of an inkjet printer system, consistent with certain disclosed
embodiments;

[0021] FIG. 6 is a diagram illustrating an example two-dimensional slice
of a three-dimensional graph that depicts the color gamut volumes of
different paper types, consistent with certain disclosed embodiments.

DETAILED DESCRIPTION

[0022] The following detailed description refers to the accompanying
drawings. Wherever possible, the same reference numbers are used in the
drawings and the following description refers to the same or similar
parts. While several exemplary embodiments and features of the present
disclosure are described herein, modifications, adaptations, and other
implementations are possible, without departing from the spirit and scope
of the present disclosure. Accordingly, the following detailed
description does not limit the present disclosure. Instead, the proper
scope of the disclosure is defined by the appended claims.

[0023] Generally, inkjet printer systems can be configured using
parameters, such as color management controls. Examples of color
management controls can include, but are not limited to, total area
coverage, ink limits, gray component replacement, color contrast, etc.

[0024] Because the type of paper used in an inkjet printer system can
greatly affect the output of the system, such as printed color documents,
the parameters used to achieve satisfactory results of one type of paper
may be unsuitable for a different type of paper. Thus, the selection of
printer parameters is an important step when printing with an inkjet
printer system.

[0025] In some embodiments, parameters, including color management
controls, can be stored on an inkjet printer system as paper profiles or
International Color Consortium (ICC) profiles. For example, an inkjet
printer system can be purchased preloaded with three paper profiles for
three common types of printer paper (e.g., untreated/uncoated,
treated/uncoated, and treated/coated). Additionally, in some
implementations, additional paper profiles can be added to the inkjet
printer system after purchase.

[0026] In various embodiments, a paper profile can be designed to balance
various printing factors, such as cost to print, quality of the printed
output, water content in the printed output, amount of drying needed,
etc.

[0027] A paper profile can be selected (automatically or manually) when at
least one sheet of paper of a type that corresponds to a paper profile is
used by the system. Based on the paper profile, the inkjet printer system
can automatically set the parameters in accordance with the paper
profile. However, there are many types of printer paper, and an inkjet
printer system may be fed a type of printer paper that is unknown and/or
unidentified.

[0028] When an unknown type of printer paper is fed into an inkjet printer
system (i.e., a type of printer paper not known to be associated with an
existing paper profile), the system can print one or more test sheets
with color patches using sheets of the unknown type of printer paper. The
test sheets can be printed using inkjet printheads that use, for example,
aqueous (water-based) ink.

[0029] Aqueous ink differs from, for example, xerographic ink in that the
total area coverage parameter is important not just for durability of the
ink pile height, but also to avoid putting down excessive water content
that results in ink showthrough. Ink showthrough is not only visually
objectionable, but also can result in other issues, such as sheet
wrinkle, curl, cockle, etc.

[0030] In some embodiments, the inkjet printer system can include an
inline Full Width Array (FWA) spectrophotometer, such as an FWA as
described in U.S. Pat. No. 6,975,949, which is incorporated by reference
in its entirety, and the system can send the printed test sheet to be
scanned by the FWA. The FWA can determine spectral data based on the
printed test sheet, which can be used to determine measurements, such as
color brightness, color gamut volumes, color contrast, ink showthrough,
paper whiteness, etc., to determine whether the measurements are
acceptable, and/or to determine a new or existing paper profile to
associate with the unknown type of printer paper. Once the type of
printer paper is associated with a paper profile, the paper profile can
be used (based on an automatic or manual selection) when printer paper of
that type is fed into the system.

[0031] FIG. 1 is a diagram depicting an example inkjet printer system
schematic, consistent with certain disclosed embodiments. FIG. 1 is
intended merely for the purpose of illustration and is not intended to be
limiting.

[0032] As depicted in FIG. 1, inkjet printer system 100 can include, for
example, paper feed mechanism 110, inkjet printheads 120, and FWA 140. A
sheet of paper can be feed into feed mechanism 110, and follow path 130
to inline inkjet printheads 120, then to inline FWA 140, and then can be
output from the system. Accordingly, in some implementations, inkjet
printer system 100 can be a closed system with at least the
above-described components. Inkjet printer system 100 can, in further
implementations, include other components, such as, for example, one or
more motors, one or more cutting mechanisms, one or more stapling
mechanisms, user input devices, display devices, etc.

[0033] In some embodiments, an unknown type of paper can be placed into
paper feed mechanism 110. Inkjet printer system 100 can then receive an
instruction to profile the paper type. For example, an operator can
provide an indication that a new or unknown type of paper has been placed
into paper feed mechanism 110 (e.g., using a button or other type of
input mechanism). Alternatively, for example, the instruction can be
based on a determination by inkjet printer system 100 that new paper has
been added to a paper loading mechanism of the system, and/or based on a
determination that a sheet in paper feed mechanism 110 has not been
profiled.

[0034] In some implementations, inkjet printer system 100 can, in response
to the instruction, begin printing one or more test sheets with color
patches using inkjet printheads 120. Example color patches are shown in
FIG. 4 and described in further detail below.

[0035] In some embodiments, inkjet printheads 120 can use aqueous
(water-based) ink.

[0036] In various embodiments, inkjet printheads 120 can be used to print
test sheets by propelling droplets of ink onto the paper based on
parameters (e.g., color management controls) of one or more paper
profiles. A paper profile can define various parameters for use when
printing a document.

[0037] In some embodiments, when an instruction is received to profile a
paper type, the inkjet printer system 100 can print test sheets using,
for example, a testing profile (i.e., a paper profile designed for
printing test sheets), another type of pre-existing paper profile, or
manually entered parameters.

[0038] Inkjet printheads 120 can be, for example, thermal inkjet heads
that use the thermal inkjet process to move drops of ink by using a pulse
of current passed through a heating element that causes a rapid
vaporization of the ink in the chamber and forms a vapor bubble, which
causes a large pressure increase, propelling a droplet of ink onto the
paper. Surface tension of the ink, the condensation, and a contraction of
the vapor bubble pull a further charge of ink into the chamber through a
narrow channel attached to an ink reservoir.

[0039] As an additional example, inkjet printheads 120 can be
Piezoelectric inkjet heads that, instead of a heating element, use a
piezoelectric material in an ink-filled chamber behind the nozzles. When
a voltage is applied, the piezoelectric material can change shape, which
generates a pressure pulse in the fluid and can force a droplet of ink
from a nozzle.

[0040] In some embodiments, inkjet printheads 120 can apply between zero
and eight droplets of ink per dot, depending on an intended color of the
dot and the parameters.

[0041] Once a test sheet is printed, it can be scanned by FWA 140. FWA 140
can measure spectral data (as described in further detail in U.S. Pat.
No. 6,975,949) to determine, for example, color brightness, color gamut
volumes, color contrast, paper whiteness, etc. Additionally, in some
embodiments, FWA 140 can measure both sides of the paper to also
determine a showthrough level of the ink (e.g., how much ink bleeds
through the paper, if any) based on the spectral data. For example, as
depicted in FIG. 1, FWA 140 can include sensors on both sides of the
printed sheets as the sheets travel down path 130.

[0042] In some implementations, once the spectral data is measured, the
measured data can be compared to expected data associated with one or
more existing paper profiles. For example, if a testing profile is used,
one or more existing paper profiles can be associated with expected data
for paper types associated with the paper profile. In other words, a
paper type associated with a first paper profile may be expected to
produce certain spectral data when a test page is printed on the paper
type using the testing profile.

[0043] In some embodiments, inkjet printer system 100 can be a closed loop
system. For example, inkjet printer system 100 can print a test sheet,
using inkjet printheads 120, scan the test sheet, using FWA 140, and then
use the data from the scanned test sheet as feedback to adjust parameters
and print a subsequent test sheet and/or regular print jobs, as described
in further detail below.

[0044] Accordingly, if the measured data is similar to expected data of a
paper profile then the paper profile can be associated with the new or
unknown type of paper, as described in further detail below. Regular
print jobs using the new or previously unknown type of paper can be
printed using the identified paper profile.

[0045] If the measured data is not similar to expected data, then a new
paper profile can be created by printing subsequent test sheets, as
described in further detail below.

[0046] FIG. 2 is a diagram depicting a schematic side view of one example
of an FWA spectrophotometer shown scanning a printed sheet in the output
path of an inkjet printer system, consistent with certain disclosed
embodiments.

[0047] As depicted in FIG. 2, FWA spectrophotometer system 10 includes
both LED arrays 14, 16 of an illumination system (which may be mounted on
a single printed circuit board) oppositely oriented at about 45 degrees
to a printed test sheet 12 they are both illuminating. Thus they allow
perpendicular orientation, in between LED arrays 14 and 16, of a linear
reflected light optical path from 12A to the imager array 20 through
SELFOC lens 18.

[0048] Further details regarding measuring spectral data using an FWA
spectrophotometer system can be found in U.S. Pat. No. 6,975,949, which
is incorporated by reference.

[0049] FIG. 3 is a flow diagram illustrating an example method of managing
paper profiles in an inkjet printer system, consistent with certain
disclosed embodiments. The process can begin in 300 when the system
receives an instruction to profile the paper type. In some embodiments,
the instruction can be based on an input by an operator using, for
example, a button on the system, an input terminal that is part of and/or
connected to the system, or a computing device connected to the system
via a direct or network connection. For example, the operator may be
adding a new type of paper into a paper feed. As a further example, the
operator may not be aware that a paper profile exists for the type of
paper being added. As another example, the operator may have determined
that there are possible errors in a previous printout using the type of
paper and a previous paper profile (e.g., due to color drifts that may be
caused by varying area coverage input interactions with the paper
substrate and drying systems of the inkjet printer system).

[0050] In further embodiments, the instruction can be generated by the
system, when the system scans a printed document using an FWA
spectrophotometer and determines, for example, that a color level is
incorrect, that the whiteness of the paper does not match an expected
whiteness associated with a current paper profile, that there is more
than a threshold amount of showthrough of the ink, that color contrasts
and/or color/paper contrasts are incorrect, etc. In some embodiments, the
instruction can be generated by the system when any new paper is loaded
into a paper feed and/or used by the system. In further embodiments, the
instruction can be generated by the system when color drifts cause errors
in previous printouts, which are detected by the system.

[0051] In 305, the system can print a test sheet with color patches. The
color patches can be CMYK and/or RGB patches. CMYK and RGB patches can
allow for patches with limited colors, but that provide a simulation of
what kind of colors can be achieved using the test sheet and current
parameters.

[0052] In some embodiments, the test sheet can be printed using a testing
paper profile, a current paper profile (i.e., a paper profile currently
active on the system), or a selected paper profile (e.g., by an
operator). An example test sheet is shown in FIG. 4 and described in
further detail below and in U.S. Pat. No. 6,975,949.

[0053] In 310, the system can measure the patches using the FWA
spectrophotometer, as described in further detail below with regard to
FIG. 5, to determine spectral data. The spectral data can then be used to
determine various measurements, such as color, density, showthrough, and
contrast, etc.

[0054] In 315, the system can compare the measurements to expected
measurements from other paper types associated with existing paper
profiles. For example, as paper quality and cost increase, so does the
size of the achievable gamut volume. In other words, cheaper paper can
result in smaller gamut volumes. Accordingly, a gamut volume can be a
measurement used to compare to expected measurements of other paper
types. For example, cheaper paper (e.g., untreated and uncoated paper)
can be associated with a first paper profile and more expensive paper
(e.g., treated and coated paper) can be associated with a second paper
profile. Gamut volumes determined from the test sheet can be compared to
the first paper profile and the second paper profile to determine if the
type of the test sheet can be associated with either profile.

[0055] In various embodiments, gamut volume can be calculated from the
L*a*b* values in the spectral data, as discussed in further detail below.

[0056] In 320, the system can determine whether the determined
measurements are similar to expected measurements for a paper type
associated with an existing paper profile. If, in 320, the measurements
are similar to expected measurements associated with an existing paper
profile (e.g., one or more measurements are within a predetermined range
and/or threshold of the expected measurements), the process can proceed
to 355 and the system can use the existing paper profile for print jobs
that use the paper type associated with the test sheet. For example, the
system can print documents using the parameters associated with the
existing paper profile for any remaining paper that is in the paper
feeder, the system can notify an operator of the existing paper profile
(e.g., by displaying a name of the paper profile), and/or the system can
automatically use the paper profile when paper of the tested type is fed
into the system.

[0057] If, in 320, the determined measurements are not similar to expected
measurements for existing paper profiles (e.g., one or more measurements
are not within a predetermined range and/or threshold of the expected
measurements), the process can proceed to 325.

[0058] In 325, the system can perform print linearization on a second test
sheet of the tested type to verify that there are no calibration errors
or any other type of error associated with the paper, printheads of the
system, etc. If an error is determined, in some embodiments, an
adjustment can be made to the calibration parameters, an additional test
sheet can be printed, and print linearization can be performed again. If
there are no detected errors, the process can proceed to 330.

[0059] In 330, the system can adjust parameters (e.g., color management
controls). In some embodiments, the parameters can be adjusted based on
determined measurements (e.g., determined gamut volumes and/or
showthrough of a previous test sheet). For example, if the system
determines that there is non-negligible showthrough on a previous test
sheet, the total area cover can be reduced (e.g., 220% to 200%) for a
subsequent test sheet. In alternative embodiments, the system can adjust
parameters to achieve a full range of test results by incrementally
reducing or increasing parameter values for each test sheet.

[0060] For example, a first test sheet can be printed with a total area
coverage of 400%, which can be reduced incrementally from 400% down to 0%
with subsequent test sheets or until an acceptable and/or negligible
amount of showthrough occurs. As an alternative example, a first test
sheet can be printed with a total area coverage of 0%, which can be
increased incrementally from 0% up to 400% with subsequent test sheets or
until an unacceptable and/or non-negligible amount of showthrough occurs.

[0061] In 335, the system can print a subsequent test sheet with color
patches based on the adjusted parameters.

[0062] In 340, the system can measure the patches using the FWA
spectrophotometer, as described in further detail below with regard to
FIG. 5, to determine spectral data and determine measurements, such as
color, density, and showthrough.

[0063] In 345, the system can determine whether one or more measurements
are within target ranges. For example, the system can determine whether
the gamut volume and/or the showthrough are within target ranges. In some
embodiments, the target ranges can be set based on industry standard
ranges.

[0064] If, in 345, the measurements are not within the target ranges, the
process can return to 330, where the parameters are adjusted (330), color
patches are printed (335), color patches are measured (340), and it is
determined whether the measurements are within target ranges (345).
Accordingly, in some embodiments, 330-345 can be repeated until the
measurements are within the target ranges.

[0065] If, in 345, the measurements are within the target ranges, the
process can proceed to 350, and a new paper profile can be generated
based on the parameters that resulted in the measured spectral
data/measurements within the target ranges. The new paper profile can be
stored, for example, in the system.

[0066] In 355, the system can use the new paper profile for print jobs
that use the paper type associated with the test sheet. For example, the
system can print subsequent documents using the parameters associated
with the new paper profile, the system can notify an operator of the new
paper profile (e.g., by displaying a name of the paper profile), and/or
the system can automatically use the new paper profile when paper of the
tested type is fed into the system.

[0067] While the steps depicted in FIG. 3 have been described as performed
in a particular order, the order described is merely exemplary, and
various different sequences of steps can be performed, consistent with
certain disclosed embodiments. For example, in some embodiments, the
system may not perform print linearization in 325. Additional variations
of steps can be utilized, consistent with certain disclosed embodiments.
Further, the steps described are not intended to be exhaustive or
absolute, and various steps can be inserted or removed.

[0068] FIG. 4 is an example of a printed test sheet with multiple
different colors of color patches, consistent with certain disclosed
embodiments.

[0069] Printed test sheet 30 can represented a printed test sheet printed
by an inkjet printer system (e.g., inkjet printer system 100 in FIG. 1)
and/or a printed test sheet printed in 305 or 335 in FIG. 3. As depicted
in FIG. 4, printed test sheet 30 can include rows of different color
patches 31 and timing or triggering indicia marks 33. As described, and
shown in FIG. 1, printed test sheet 30 can be printed and then scanned by
an FWA spectrophotometer (e.g., FWA 140 in FIG. 1 or FWA
spectrophotometer system 10 in FIG. 2). In various embodiments, printed
test sheet 30 can be scanned to determine spectral data, which can be
converted into measurements that are used to determine if a new and/or
unknown paper type can be associated with an existing paper profile or if
a new printer profile needs to be generated, as described above.

[0070] FIG. 5 is a flow diagram illustrating an exemplary method of
measuring color patches, consistent with certain disclosed embodiments.
In some embodiments, the process described with regard to FIG. 5 can
represent a process performed using a processor and an FWA
spectrophotometer (e.g., FWA 140 in FIG. 1 or FWA spectrophotometer
system 10 in FIG. 2).

[0071] The process can begin in 500 when a printed test sheet is received
at an FWA. In 510, the FWA can scan the printed test sheet to determine
spectral data. In some embodiments, the FWA can include scanners that
scan both sides of the paper.

[0072] In 520, the spectral data can be used by the processor to determine
measurements such as color levels of the patches. For example, the
processor can measure color levels based on spectral data associated with
CMYK (cyan, magenta, yellow, and black) color patches and RGB (red,
green, blue) color patches.

[0073] In 530, the spectral data can be used by the processor to determine
measurements such as a whiteness level of the printed test sheet.

[0074] In 540, the processor can convert the spectral data to color
density to determine a showthrough level. For example, spectral data from
the reverse side of the printed test sheet (i.e., the opposite side from
the printed color patches) can be converted to color density to determine
a showthrough level.

[0075] While the steps depicted in FIG. 5 have been described as performed
in a particular order, the order described is merely an example, and
various different sequences of steps can be performed, consistent with
certain disclosed embodiments. For example, 520-540 can be performed in
any order and/or simultaneously. Additional variations of steps can be
utilized, consistent with certain disclosed embodiments. Further, the
steps described are not intended to be exhaustive or absolute, and
various steps can be inserted or removed.

[0076] FIG. 6 is a diagram illustrating an example two-dimensional slice
of a three-dimensional graph that depicts the color gamut volumes of
different paper types, consistent with certain disclosed embodiments. As
shown in FIG. 6, graph 600 can be a two-dimensional slice of a
three-dimensional graph of L*a*b*, with L* representing lightness and a*
and b* representing color-opponent dimensions. For example, graph 600 can
represent a graph of a*b*.

[0077] Graph 600 can depict color gamut volumes for three different paper
types. In some embodiments, the color gamut volumes can represent known
color gamut volumes associated with the three different paper types, and
can be used when comparing spectral data measured using an FWA with known
color gamut volumes to determine if an existing paper profile can be used
for a tested paper sheet type (e.g., 315 and 320 in FIG. 3).

[0078] For example, volume 610 can represent a color volume for treated
and coated paper, volume 620 can represent a color volume for untreated
and uncoated paper, and 630 can represent a color volume for treated and
uncoated paper.

[0079] As the paper quality and cost increase, so does the size of the
achievable gamut. Graph 600 gives a general example of the differences.
Using the basic patches of 100% C, M, Y, K, R, G, B, and W (white) a
gamut volume can be calculated from the L*a*b* values determined using an
FWA (e.g. 510 in FIG. 5). For example, the gamut volumes shown can be
98,683 for volume 620, 139,046 for volume 630, and 217,273 for volume
610. Thus, a tested paper type that results in spectral data converted
into volumes similar to the known volumes (e.g., within a range and/or
threshold) can use a paper profile associated with the paper type with
the similar volume. Checking the L*a*b* of paper whiteness for a printed
test sheet can also be used to determine which known paper profiles to
use or if a new profile is needed.

[0080] While the teachings has been described with reference to the
example embodiments thereof, those skilled in the art will be able to
make various modifications to the described embodiments without departing
from the true spirit and scope. The terms and descriptions used herein
are set forth by way of illustration only and are not meant as
limitations. In particular, although the method has been described by
examples, the steps of the method may be performed in a different order
than illustrated or simultaneously. Furthermore, to the extent that the
terms "including", "includes", "having", "has", "with", or variants
thereof are used in either the detailed description and the claims, such
terms are intended to be inclusive in a manner similar to the term
"comprising." As used herein, the term "one or more of" with respect to a
listing of items such as, for example, A and B, means A alone, B alone,
or A and B. Those skilled in the art will recognize that these and other
variations are possible within the spirit and scope as defined in the
following claims and their equivalents.